The star filmed on 120 intricate sets for the new postapocalyptic movie.

The film adaptation of Phillip Reeve’s futuristic steampunk novel, Mortal Engines has landed in theaters after several years in development and Icelandic actress Hera Hilmar recounted her process of trying to understand the complexly crafted world.

"I remember reading it and just going through these moving cities [that are] eating each other [with] this kind of crazy female heroine in the middle of all that chaos,” she said.

Mortal Engines follows Hester Shaw (Hilmar), a fugitive assassin with a personal vendetta, occupying a society that has been built up hundreds of years after civilization was destroyed by a cataclysmic event. The heroine emerges as the only who can stop London — now a giant, predator city on wheels — from devouring everything in its path.

Filming took place in New Zealand, the home of Mortal Engines screenwriter Peter Jackson (Lord of the Rings trilogy, The Hobbit trilogy), where the actors interacted with over 120 "fully intricate" sets that were only amplified in postproduction with visual effects.

“There's a town called Airhaven in the [adaption] and it was completely built. It hung from the ceiling. It had like a bar, it had bridges, docks for the airships,” Hilmar said. "It was kind of like being in an amusement park.”

The postapocalyptic adventure film also dives into human relationships with semi-robotic beings known as Stalkers, with one called Shrike (Stephen Lang) acting as Hester's guardian. Hilmar decided to challenge herself by adapting her social communications around the character.

"I think it's really beautiful and unique to understand how you'd communicate with someone who is not human, doesn't have a heart, doesn't have a soul, but happens to be as soulful and have as big a heart in the ways that he does," the actress told The Hollywood Reporter.

Hilmar admitted that while the storyline is hard at first to digest, viewers should stick around and become enveloped by the rich material.

"It's a lot to take in to begin with," she said. "I think people should go and get the books to begin with and just look into it."

Mortal Engines is available in theaters nationwide Dec. 14.

Watch the video above to hear Hilmar tease her initial conversations with Peter Jackson, discuss her ambitions to play unique roles and more.